Permastone Painting Test

I applied a few test swatches of paints to the rough side of the Permastone tile I made in the previous post. Here is a photo of it with a closeup. I used acrylic, gouache, and oil paints.

On the bottom, I coated the tile with a couple coats of Golden’s GAC 100 medium, which is what they recommend as a sizing barrier for oils when painting on paper or canvas. I thought it might give a little more stability and protection to the paint layer, and reduce the absorbency of the tile. I used it under both acrylics and oils. It made the tile a shade darker in tone, the paints dried a bit more slowly, and had more gloss to them; otherwise, I didn’t notice too much of a difference.

I’m very pleased with how well this surface accepts these paints. They flow very nice and softly. Gouache in particular behaves very well, and the raw umber oil layer dried very quickly on the bare tile, as I expected.

I’d like to try and see if I can get it thinner, perhaps by troweling thin layers onto a sheet of canvas, or thinning it more and brushing it on, much like the way I make gesso panels. The surface will scratch easily so you have to be careful with it.

I noticed this morning (about 1 day later) that all the oils painted on the bare Permastone tile were touch dry. I rubbed that area with a cotton swab and no paint came off, so it didn’t appear to be under bound. The oil paints on the raw umber undertone were dry except for the yellow (PY3,) and all the oils on the GAC 100 were all still wet.

I’ve since been trying to come up with a substitute for this Permastone tile by using gypsum and rabbit skin glue, but in a thicker mix than what I use for gesso panels. Unfortunately, it hasn’t been as successful. The alternative takes longer to dry, up to a week; although, the surface is just as good, if maybe a bit softer.